I was wondering if there was a way i could open a pdf, add a password, and save and close it all through either command-line or powershell. I am unsure of how I would go about doing this, specifically adding the security to the document (I am able to open the document I want to secure).
No such command line. The primary scripting API to Acrobat is OLE, but that doesn't allow passwords. The free Adobe Reader has a minimal API. (All Acrobat developers will need the Acrobat SDK).